In a related art technique, as a best-known and widely used laminated glass among laminated glasses formed by bonding a plurality of superposed glass plates, it could be a laminated glass formed by bonding the glass plates together through an interlayer, which is completed by inserting a resin sheet made of PVB (polyvinyl butyral) as the interlayer between the glass plates and arranging them in layers then heating and pressing these interlayer and glass plates.
In a process in which the glass plates are bonded, if air bubbles remain between the glass plates, even if the air bubbles are minute, not only light transmittance is deteriorated, but this brings about a decrease in adhesive strength of the bonded glass plates, then there arises a problem such as exfoliation. Therefore, it is essential that before a main bonding process in which the glass plates are bonded together by entirely melting an adhesive film by the application of heat under a constant pressurization condition in an autoclave, a preliminary bonding process that sufficiently carries out deaeration or degassing of the air bubbles between the glass plates through heating and pressurization should take place.
In particular, since the window glass of the vehicle has a three-dimensional shape that curves in two directions, in order to degas the air bubbles between the superposed two glass plates, an idea of uniformly pressing the glass plates from both surfaces is required.
For example, Japanese Patent Provisional Publication Tokkaisho No. JP61-169248 discloses a device for joining at least one sheet of glass and at least one film of plastic material by calendering. The device has a series of pressure rollers mounted side-by-side in a flexible manner and a series of counter pressure rollers mounted in a flexible manner and cooperating with the pressure rollers. The pressure rollers and the counter pressure rollers are each mounted at an extremity of a piston rod. The other extremity of the piston rod bears a pressure piston actuated by pneumatic pressure and moving in a pneumatic casing (Patent Document 1).
Further, Japanese Patent Provisional Publication Tokkaihei No. JP2-279544 discloses a preliminary bonding device that performs the preliminary bonding by passing a laminated member for a laminated glass between a plurality of pressurizing rolls which are arranged at upper and lower sides. The preliminary bonding device has a mechanism by which all of the pressurizing rolls can rotate in a surface substantially perpendicular to a passing direction of the laminated member of the laminated glass (Patent Document 2).
Furthermore, in Japanese Patent Provisional Publication Tokkosho No. JP47-2265, for the purpose of rolling out a spherically curved glass plate, which has a synthetic resin film of intermediate insertion, to a pre-complex, a rolling device has a revolution frame that is capable of turning on an axis substantially perpendicular to a rolling direction, and a number of pressure rolls that act on upper and lower glass plates by their respective springs are arranged in the revolution frame. The rolling device allows each pressure roll to be fixed to the revolution frame together with a structure part which supports the pressure roll and is secured to the revolution frame and together with the spring independently of the other pressure rolls. Also each pressure roll is combined with a pressure roll unit that can detach from the revolution frame independently. In addition, the pressure roll unit is secured to the revolution frame so as to be adjusted laterally in the rolling direction for coping with a different curvature of the pre-complex (Patent Document 3).
Moreover, Japanese Patent Provisional Publication Tokkohei No. JP3-21494 discloses a curved roll apparatus that has a pair of flexible rolls and a plurality of backup rolls that limit a relative position of each part of the flexible roll. At least a curved portion of each flexible roll is hollow inside, and the flexible roll has therein a spiral member (Patent Document 4).
In addition, Japanese Patent Provisional Publication Tokkai No. JP2002-167242 discloses a preliminary bonding device of a laminated glass which presses a carried-in/out curved laminated glass sandwiching an interlayer from both curved surfaces thereof by a plurality of roll units that are capable of adjustment of angle along a longitudinal cross section shape. The preliminary bonding device has a carrying-in carrying-out means that carries in/out the curved glass with an inclination angle changed and a pressing roll unit formed by an upper side roll unit and a lower side roll unit. The preliminary bonding device also has a roll pressing means having upper and lower pressing rolls disposed so as to pair in a normal direction of the curved glass surface, a pressing cylinder provided for each pressing roll to press the roll against the glass surface and a pressure control valve to keep a pressure in the pressing cylinder constant, an angle adjusting means which supports holding points of the upper and lower pressing cylinders so that positions of the holding points of the cylinders can shift within respective long holes provided in horizontally set upper and lower lateral frames to adjust a pressing angle against the curved glass, a rotating means which forms a rectangular main supporting frame by connecting both ends of the upper and lower lateral frames to longitudinal frames and allows a rotation of the main supporting frame on a supporting axis set at a substantially center part of each longitudinal frame, and a driving means that moves the curved glass between the upper and lower side pressing roll units with its moving speed adjusted. The upper and lower side pressing roll units are set in the normal direction of the curved glass surface in accordance with a carrying-in/out speed of the curved glass (Patent Document 5).